The precise localization of the chitin synthetase zymogen in the plasmalemma of yeast will be further studied and attempts will be made toward its solubilization. A chemical and enzymatic study of the plasma membrane will be undertaken with special emphasis on its role in the synthesis of cell wall polysaccharides. The recently obtained yeast mutants, which are blocked before or at septum formation will be the subject of additional investigations, and new mutants of this type will be obtained. Efforts will continue to elucidate possible differences between glycogen synthetase of the wild-type and of a glycogenless mutant strain.